Animated display device



Dec. 4, 1956 T. EDMONDS ANIMATED DISPLAY DEVICE Filed Jan. 9, 1953 TOCOMMUTRTOR THEoDo E EDM oNDS,

INVENTOR.

ATToRA/E United States Patent ANIIVIATED DISPLAY DEVICE TheodoreEdmonds, Danvers, Mass., assignor to Sylvania Electric Products Inc.,Salem, Mass., a corporation of Massachusetts Application January 9,1953, Serial No. 330,513

11 Claims. (Cl. 315-169) This invention relates to electroluminescentdisplay devices.

Electroluminescent lamps generally comprise a layer ofelectroluminescent phosphor, or of phosphor embedded in a dielectricmaterial, between two electrodes which can be connected to anappropriate source of voltage, the layer containing the phosphor beingreferred to herein as a screen. One such lamp is shown, for example, inU. S. Patent 2,566,349, issued September. 4, 1951, to Eric L. Mager.

An object of the present inventionis the production of a pattern on sucha screen.

Another object is to make the pattern variable, and a particular objectis to make it variable in color.

In one embodiment of the invention, these results are achieved bycoating a piece of so-called conducting glass with a layer of phosphorembedded in a dielectric mate rial, and making the other electrode aconductive coating over said phosphor layer and formed into the desiredpattern. If the pattern contains two electrically insulated coatings,and the phosphor used is one whose color changes with frequency, such asthe copper and lead activated zinc sulphide of copending applicationSerial No. 180,783, filed August 22, 1950, by Elmer C. Payne, then oneof the coatings will luminesce one color if connected to low frequency,such as 60 cycles per second, and the other coating will luminesceanother color if connected to a higher frequency, such as 500 cycles ormore per second. The color of either or both coatings can be changed,for the same phosphor, by changing the frequency.

If the coating is divided into several areas, insulated from each other,then the color of any or all of the areas can be changed. For example,if the coating consists of a general background area, with several otherareas spaced apart from it laterally in the form of a series of figuresof some sort, then a figure can be made to seem to move from oneposition to another, by switching the figures in sequence from onefrequency to the other.

Other objects, advantages and features of the invention will be apparentfrom the following specification, taken in connection with theaccompanying drawings, in which Fig. l is a back view of one embodimentof the invention, showing the pattern of the coating on the back, andits connections to the power source; and Fig. 2 is a side view of thelamp of said device.

In the figures, the glass plate 1 carries the transparent conductivecoating 2 of stannous chloride or the like, as is now well-known in theart, thus forming a so-called conductive glass. A coating 3 of a mixtureof phosphor and dielectric material, such as shown for example incopending application Serial No. 230,596, filed June 8, 1951 by Lowry,Mager and Butler, is placed over the conductive coating 2, which is atground potential. The metal coating 4, broken up into the areas 5, 6, 7,8, 9, which are spaced from each other by an amount suflicient toelectrically insulate them from each other by the spacing 'ice 2 shownas lines 10, -11, 12, 13, is placed over the phosphordielectric coating3. t

In the particular embodiment shown, a copper and lead activatedelectroluminescent zinc sulfide is used as the phosphor, and the metalarea 6 is then connected to a potential of low frequency, say cycles persecond, to luminesce green, representing a grass-covered hill, forexample, and the area 5 is connected to a potential of 500 cycles orhigher, torepresent' the sky. The areas 7, 8 and 9 which represent a carin successive positions going down the hilland out into space, will thenbe connected to a potential of 60 cycles per second when the car is tobe shown and to a source of 500 cycles per second when the car is not tobe shown. Thus by connecting area 7 to a potential of 60 cycles persecond, the pattern of a car appears in area 7 and it will not appear inthe areas 8 and 9 if the latter are at that time connected to apotential of 500 cycles per second, so that areas 8 and 9 fade into thebackground of blue area 5. If then the area 7 is switched to 500 cycles,the car disappears there, and if the area 8 is changed to 60 cycles thecar appears in area 8, as if it had moved downward from 7 to 8. By thenswitching area 8 to the higher frequency and 9 to the lower, the carwill appear to move to position 9, as if it had jumped off the hill andout into space.

The area 6 is permanently connected to a 60-cycle source to representthe green hill, and area 5 to 500cycles to represent the blue sky. Thepotentials of the areas 8, 9 and 10, representing the car, are switchedfrom one frequency to another by the commutator 14, rotated by the motor15, thetwo being connected by the shaft 16. The commutator drum 17 is ofinsulating material with the metal segments 18, 19, 20, 21, 22 settherein in position to contact the brushes 23, 24, 25, connectedrespectively to areas 7, 8, 9 of the lamp. The segment 20 is long enoughto contact both brushes 24 and 25, and segments 19 and 22 are connectedtogether inside the drum 17. Rings 26 and 27 extend around thecircumference of drum 17, ring 26 being connected to segments 19, 20 and22, and ring 27 to segments 18 and 21. Brushes 28, 29 bear,respectively, on rings 26, 27, connecting the latter, respectively, tosources of power of 500 cycles per second and of 60 cycles per second,as shown, the other sides of the lines being grounded for convenience,or connected back to the transparent conduction coating 2. Thecommutator segments 18, 19, 20, 21, 22 for the first two steps of thecars progress are shown in the figure.

Although for convenience the invention has been described in connectionwith the particular embodiment above, its usefulness is more general,and it can be used in various places where a luminous pattern of morethan one color is desired, or a pattern variable with time. The devicecan be used to present not only pictures, but also other information inthe form of lettering, numbering or other symbols.

In the foregoing specification the frequency for the blue color has beentaken as 500 cycles per second for convenience, but the light willordinarily be much more blue it a frequency of 5000 cycles per second isused.

What I claim is:

1. An electroluminescent display device comprising a layer ofelectroluminescent material whose emission color varies with thefrequency of the field applied thereto, at least one electrode on oneside of said layer, and at least two electrodes on the other side ofsaid layer and electrically insulated from each other.

2. The combination of claim 1, and means for supplying a potential ofdifferent frequency to each of said electrodes.

3. An electroluminescent display device comprising a layer ofelectroluminescent material whose emission color varies with thefrequency of the applied field, at least one electrode on one side ofsaid layer and at least two 'lec trodes on the other side of said layerand electrically in- 7. The combination of claim 6, and means forapplymg a potential sequentially to some of ai coatings in the series. I

8. The combination of claim 6, means for displaying a potential to atleast some of the areas, and means for changing the frequency of thpotential applied to some of the areas.

9. The combination of claim 6, i n which the coatings in the series arearranged in a predetermined design.

10. An electroluminescent display devieecomprising a layer of'copper-and-le 'ad activated 'z'in'c sulfide electroluminescent materialwhose emission color varies With the en at the ,fl lda pliqd th eto at.least. oae trode on one side of said layer, and at lea st two electrodeson the other side of said layer and electrically insulated from eachother.

11. An electroluminescent display device comprising a er q ve le trq umae a nt m te lrv lh e emis vefipl varies with the frequency of the fieldapplied thereto, meansfor rnaking. electrical connection to one sidle ofsaidv 9i eefis d l a i t' s l c i i t a uflk a P9 vn bf theb h l d q jal, 1' l mite e sr q mf ks ifig elesti a aectiqa an th r Pqr qm Sai etheside electrically insulated from 'said first-mentioned portion.

n reiites beta in "the 'file a this partial UNITED STATES PATENTS

